All language subtitles for SciShow - What Really Happened with Typhoid Mary_ (720p).English

If you’re one of the almost five billion
people with access to clean water and good

hygiene, there are a lot of reasons to be
thankful.

For one thing, you don’t have to worry about
typhoid fever.

The disease, which is caused by a bacteria
called Salmonella typhi, is spread by infected

food, water, or contact with a sick person’s
feces or urine, and symptoms include vomiting,

diarrhea, and a nasty rash.

But some people don’t have any symptoms
at all.

They’re carriers, and can still spread the
disease, even though they aren’t sick themselves.

Mary Mallon, better known as Typhoid Mary,
was one of those carriers.

In the early 1900s, typhoid fever was mainly
a problem in poor urban communities - but

suddenly, about 3,000 people, including rich
families, got sick.

And it was all thanks to Mary Mallon.

Mallon immigrated from Ireland to New York
City in 1883 and started working as a cook

for wealthy families.

We don’t know when she originally got typhoid
fever, but she was definitely a carrier, and

the families she worked for always got sick
after she started cooking for them.

But by the time someone came to investigate,
Mary had always moved on to the next house.

Her luck ran out in 1906, while she was working
for a family in Oyster Bay, on Long Island

in New York.

The family came down with typhoid fever — which
was totally unexpected, because Oyster Bay

was home to the rich and famous, and typhoid
was considered a disease that mainly affected

the poor.

So the house’s landlord hired George Soper,
a freelance sanitary engineer, to find the

source of the outbreak.

All the water sources in the house turned
up clean, and Soper eventually started looking

into Mary’s employment history.

Seven families she’d worked for — a total
of 22 people — had reported cases of typhoid

fever, including one girl who had died.

It didn’t take Sherlock Holmes to put the
pieces together: Mary was a typhoid carrier.

Even if they feel fine, carriers carry the
typhoid-causing bacteria in their cells for

years, which means they can get other people
sick, too.

The carrier doesn’t feel sick, but the bacteria
are still in their feces and urine, so they

can spread the disease if they don’t wash
their hands well.

But even though Mallon was a cook, at first
it didn’t make sense that she’d spread

typhoid so easily.

Even if she didn’t wash her hands, any bacteria
in her food should have died from the high

temperatures involved in cooking.

Except it turned out that she was preparing
non-cooked foods, too — one of her most

popular dishes was peach ice cream, which
was packed with raw peaches.

After Soper’s investigation, Mallon was
forced to have her feces tested for typhoid.

The test was positive, so she was quarantined
in a small shack on North Brother Island,

a tiny island east of Manhattan.

Mary Mallon was the first known typhoid carrier
in the United States, and her case wasn’t

handled too well.

Health officials didn’t do a great job explaining
to Mallon why she was spreading disease even

though she didn’t feel sick, and they didn’t
prepare her for life as a carrier.

Three years later, she was released from quarantine,
but she had to promise not to go back to cooking.

Mallon didn’t have a way to make a decent
living doing anything else, though, so when

the city lost touch with her, she went right
back to the kitchen.

Five years later, typhoid fever broke out
at Sloane Maternity Hospital in Manhattan,

infecting 25 workers and killing two people.

Health officials went to the hospital … and
found Mary Mallon working there as a cook

under a new name, Mary Brown.

So she was taken back to North Brother Island,
where she was quarantined for more than 23

years, until she died in 1938.

Even though Typhoid Mary was the first known
typhoid carrier in the U.S., she wasn’t

the last.

Plenty of other New Yorkers carried the disease,
but since Mary had gone back to cooking despite

knowing she could infect people, the public
turned against her.

These days, typhoid can usually be treated
with antibiotics, and there are vaccinations

for people who live in or travel to parts
of the world where it’s common.

And hopefully, as we keep working to get clean
water and sanitation to people who need it,

typhoid fever will become less of a problem.

Carriers are kept under close watch, but as
long as they aren’t working in jobs like

cooking, they’re free to live their lives.

Mary Mallon wasn’t so lucky.

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